[Xen-changelog] [xen-unstable] hvm: fix single stepping on debugger

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1226404023 0
# Node ID 07d0be88571fa4dfbf3449069c78c08acc09b2da
# Parent  7be8e7eefbd79e7bb823b20eadfbdd1fec483d93
hvm: fix single stepping on debugger

The debuggee domain will die with unexpected trap
on single stepping of emulated instruction.

Signed-off-by: Kouya Shimura <kouya@xxxxxxxxxxxxxx>
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
 xen/arch/x86/hvm/svm/svm.c      |   24 +++++++++++++++++-------
 xen/arch/x86/hvm/vmx/realmode.c |   20 ++++++++++++++------
 xen/arch/x86/hvm/vmx/vmx.c      |   25 ++++++++++++++++++-------
 3 files changed, 49 insertions(+), 20 deletions(-)

diff -r 7be8e7eefbd7 -r 07d0be88571f xen/arch/x86/hvm/svm/svm.c
--- a/xen/arch/x86/hvm/svm/svm.c        Tue Nov 11 11:35:00 2008 +0000
+++ b/xen/arch/x86/hvm/svm/svm.c        Tue Nov 11 11:47:03 2008 +0000
@@ -739,6 +739,23 @@ static void svm_inject_exception(
     struct vmcb_struct *vmcb = curr->arch.hvm_svm.vmcb;
     eventinj_t event = vmcb->eventinj;
 
+    switch ( trapnr )
+    {
+    case TRAP_debug:
+        if ( guest_cpu_user_regs()->eflags & X86_EFLAGS_TF )
+        {
+            __restore_debug_registers(curr);
+            vmcb->dr6 |= 0x4000;
+        }
+    case TRAP_int3:
+        if ( curr->domain->debugger_attached )
+        {
+            /* Debug/Int3: Trap to debugger. */
+            domain_pause_for_debugger();
+            return;
+        }
+    }
+
     if ( unlikely(event.fields.v) &&
          (event.fields.type == X86_EVENTTYPE_HW_EXCEPTION) )
     {
@@ -764,13 +781,6 @@ static void svm_inject_exception(
     else
     {
         HVMTRACE_2D(INJ_EXC, trapnr, errcode);
-    }
-
-    if ( (trapnr == TRAP_debug) &&
-         (guest_cpu_user_regs()->eflags & X86_EFLAGS_TF) )
-    {
-        __restore_debug_registers(curr);
-        vmcb->dr6 |= 0x4000;
     }
 }
 
diff -r 7be8e7eefbd7 -r 07d0be88571f xen/arch/x86/hvm/vmx/realmode.c
--- a/xen/arch/x86/hvm/vmx/realmode.c   Tue Nov 11 11:35:00 2008 +0000
+++ b/xen/arch/x86/hvm/vmx/realmode.c   Tue Nov 11 11:47:03 2008 +0000
@@ -149,17 +149,25 @@ static void realmode_emulate_one(struct 
             hvmemul_ctxt->exn_insn_len = 0;
         }
 
-        if ( curr->arch.hvm_vcpu.guest_cr[0] & X86_CR0_PE )
+        if ( unlikely(curr->domain->debugger_attached) &&
+             ((hvmemul_ctxt->exn_vector == TRAP_debug) ||
+              (hvmemul_ctxt->exn_vector == TRAP_int3)) )
+        {
+            domain_pause_for_debugger();
+        }
+        else if ( curr->arch.hvm_vcpu.guest_cr[0] & X86_CR0_PE )
         {
             gdprintk(XENLOG_ERR, "Exception %02x in protected mode.\n",
                      hvmemul_ctxt->exn_vector);
             goto fail;
         }
-
-        realmode_deliver_exception(
-            hvmemul_ctxt->exn_vector,
-            hvmemul_ctxt->exn_insn_len,
-            hvmemul_ctxt);
+        else
+        {
+            realmode_deliver_exception(
+                hvmemul_ctxt->exn_vector,
+                hvmemul_ctxt->exn_insn_len,
+                hvmemul_ctxt);
+        }
     }
 
     return;
diff -r 7be8e7eefbd7 -r 07d0be88571f xen/arch/x86/hvm/vmx/vmx.c
--- a/xen/arch/x86/hvm/vmx/vmx.c        Tue Nov 11 11:35:00 2008 +0000
+++ b/xen/arch/x86/hvm/vmx/vmx.c        Tue Nov 11 11:47:03 2008 +0000
@@ -1118,6 +1118,24 @@ void vmx_inject_hw_exception(int trap, i
 void vmx_inject_hw_exception(int trap, int error_code)
 {
     unsigned long intr_info = __vmread(VM_ENTRY_INTR_INFO);
+    struct vcpu *curr = current;
+
+    switch ( trap )
+    {
+    case TRAP_debug:
+        if ( guest_cpu_user_regs()->eflags & X86_EFLAGS_TF )
+        {
+            __restore_debug_registers(curr);
+            write_debugreg(6, read_debugreg(6) | 0x4000);
+        }
+    case TRAP_int3:
+        if ( curr->domain->debugger_attached )
+        {
+            /* Debug/Int3: Trap to debugger. */
+            domain_pause_for_debugger();
+            return;
+        }
+    }
 
     if ( unlikely(intr_info & INTR_INFO_VALID_MASK) &&
          (((intr_info >> 8) & 7) == X86_EVENTTYPE_HW_EXCEPTION) )
@@ -1134,13 +1152,6 @@ void vmx_inject_hw_exception(int trap, i
                          TRC_PAR_LONG(current->arch.hvm_vcpu.guest_cr[2]));
     else
         HVMTRACE_2D(INJ_EXC, trap, error_code);
-
-    if ( (trap == TRAP_debug) &&
-         (guest_cpu_user_regs()->eflags & X86_EFLAGS_TF) )
-    {
-        __restore_debug_registers(current);
-        write_debugreg(6, read_debugreg(6) | 0x4000);
-    }
 }
 
 void vmx_inject_extint(int trap)

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